A communication power supply is an equipment for supplying energy for a communication equipment such as communication base station or communication machine room. A switching rectifier is the core constituent component of the communication power supply. For the sake of requirement of high reliability in the field of communication, it is required that a communication power supply is able to supply energy for a communication equipment under various conditions. This requires that the switching rectifier can start with load under various conditions. For example, the switching rectifier is required to start with full load in an environment of −40 degrees centigrade, or start with full load when the communication equipment is powered by a fuel generator, and the like. In addition, industry standards limit amplitude of output voltage overshoot and soft-start time in switching on/off. Since environment conditions in which a communication equipment is applied are different, it is necessary to establish a reasonable soft-start strategy, such that the switching rectifier may start successfully under any condition.
Unfortunately, there is an absence of a switching rectifier suitable for various application environments at present.